320/28 Bearing Dimensions

Tolerances and fits for 320/28

FULI makes 320/28 to P0 as standard, with P6 on request. P0 is the Normal tolerance class of ISO 492; P6 limits are tighter. These are the P0 limits for the 28 × 52 × 16 mm size.

Δdmp and ΔDmp: deviation of the mean bore and mean outside diameter in one radial plane. ΔTs: assembled width of cone and cup, from the ISO 492 table for metric tapered roller bearings. Cone width B and cup width C: 0 / −120 µm each.

Shaft and housing fits (general guidance)

For an inner ring that turns with a solid steel shaft under normal load, bearing makers’ fit tables give 28 k5 for the shaft of 320/28. The cup usually sits in an H7 or J7 housing bore so that it can be moved when the pair is adjusted.

Taking the loosest and the tightest combination of limits, a P0 320/28 on a 28 mm k5 shaft has 2 to 23 µm interference. Its cup has 0 to 46 µm clearance in an H7 bore and 12 µm interference to 34 µm clearance in a J7 bore.

This is general guidance, not a FULI specification. Heavy or shock loads, a hollow shaft, a thin-walled, split or light-alloy housing, or a large temperature difference between shaft and housing call for other classes, and the drawing of your machine takes priority.

If the outer ring turns and the shaft stands still, as in an idler pulley or a wheel hub, the fits are reversed: the housing gets the interference fit (for example N7 or P7) and the shaft a sliding one (g6 or h6).

Sources: ISO 492 tables as printed in the NTN catalogue CAT. No. 2203/E (Tables 6.4 and 6.5) and the RKB tolerance catalogue; ISO 286-2 for the seats; SKF and NTN fit tables for the shaft and housing classes.

320/28 compared with nearby sizes

320/28 measures 28 × 52 × 16 mm: bore d, outside diameter D and total width T.

30205 has the same 52 mm outside diameter with a 25 mm bore, so it fits the same housing bore on a smaller shaft.

32205 has the same 52 mm outside diameter with a 25 mm bore, so it fits the same housing bore on a smaller shaft.

In the 320 series the sizes either side of 320/28 are 32005 for a 25 mm shaft and 32006 for a 30 mm shaft.

Cr and weight from FULI's catalog; — = not listed on this site.

320/28 weight, load ratings and speed

FULI's catalog gives the weight of 320/28 as about 0.142 kg, so 100 bearings weigh about 14.2 kg and 1,000 about 142 kg before packing. The weight is for the cone and cup together.

320/28 has a dynamic load rating Cr of 31.10 kN and a static load rating C0r of 39.80 kN. Cr is the load used to work out rating life; C0r is the reference for loads carried while the bearing is stationary or turning slowly.

Values from FULI's catalog; confirm for your application.

320/28 cone and cup

320/28 is supplied as a complete bearing: the cone (inner ring with rollers and cage) and the cup (outer ring). The total width T of 16 mm applies when the two are assembled; the cone and the cup on their own are each narrower. Tell us if you need only the cone or only the cup.

Tapered roller bearings carry radial load and axial load in one direction, so 320/28 is normally mounted as one of a pair facing each other, and the end play or preload is set when the pair is adjusted on the shaft. That is why FULI lists the clearance as set during mounting, not as a C-class value.

320/28 dimensions in inches

The nearest common inch shaft size to the 28 mm bore of 320/28 is 1-1/8 in (28.58 mm), 0.58 mm larger than the bore, so 320/28 will not go on it. Inch shafts need an inch bearing, not a metric one with a sleeve or shim.

Converted at 1 in = 25.4 mm and rounded to four decimals. The bearing itself is made to the millimetre sizes.

Grease for 320/28

FULI supplies tapered roller bearings rust-protected and normally without grease; grease is added when 320/28 is mounted. Relubricating 320/28 from the side takes about 4.16 g each time by the formula in our grease calculator: 0.005 × D × T = 0.005 × 52 × 16.

How FULI supplies 320/28

The standard 320/28 from FULI has GCr15 chrome steel rings and rollers and P0 precision, with P6 on request. Where an order states a requirement for the total width T (16 mm for 320/28) or the cone height, each set is checked on a height gauge.

Rings are marked with a brand you are authorised to use, with the FULI brand, or left neutral, as your order states. The box is printed with the model, precision class and brand.

Inquiries that leave out the prefix or suffix letters are the usual cause of a wrong quote, so write the full designation, for example 320/28.

Tools and guides for 320/28

• Bearing size finder: look up a size from bore, OD and width
• Bearing weight chart
• Bearing grease fill calculator
• Shaft and housing tolerance chart
• Tapered roller bearing number lookup
• Bearing lubrication basics
• Ball bearing vs roller bearing
• How to choose wheel hub bearings
• All bearing products and model pages